9th Class
Science
Force and laws of motion
Question Bank
Force and Laws of Motion
question_answer
Three equal weights of mass 2 kg each are hanging on a string passing over a fixed pulley as shown in the fig. What is the tension in the string connecting the weights B and C?
A) Zero
B) 13 N
C) 3.3 M
D) 19.6 N
Correct Answer:
B
Solution :
Referring figure\[,\] \[2g-{{T}_{1}}=2a\] ? (i) \[2g-{{T}_{1}}-{{T}_{1}}=2a\] ? (ii) and \[{{T}_{1}}-2g=2a\] ? (iii) Adding equations (i), (ii) and (iii), we get \[2g=6a\] From equation (i), \[\Rightarrow \] \[a=g/3\] \[2g-{{T}_{1}}=\frac{2g}{3}\] \[\Rightarrow \] \[{{T}_{1}}=\frac{4g}{3}=\mathbf{13}\,\,\mathbf{N}\]